Study On The Germination And Storage Of Lycoris Aurea Polle

Lycoris aurea,a perennial bulbous flower of the Amaryllidaceae family and Lycoris genus,is known for its strong resistance,wide adaptability,excellent landscape application prospects,and medicinal value.In recent years,the demand for breeding and quantity of new Lycoris aurea varieties has increased,and hybrid breeding using rich germplasm resources within the genus is the main way to cultivate new varieties.In cross breeding,the flowering periods of the parent and the parent are basically the same,however,Lycoris plants are divided into two types,spring and autumn,based on the timing of leaf emergence,and their flowering periods do not coincide.Therefore,research on pollen viability and storage is necessary to solve the isolation problem caused by time or space during hybrid breeding,without the need for pollen collection in the same time and space.In this study,Lycoris aurea from Guizhou Province was used as the research material.Field observations were conducted to record the phenology and morphology of Lycoris aurea flowers.The optimal conditions for Lycoris aurea pollen germination were determined using in vitro culture,and pollen viability was measured using staining methods.Additionally,the effects of different drying treatments and storage temperatures on pollen viability were explored.The aim of this study was to provide a theoretical basis and technical guidance for the development and utilization of Lycoris plants and the selection of new varieties.The main research results are as follows:（1）The flowering phenology and morphological characteristics of Lycoris aurea showed that the flowering period of Lycoris aurea was calculated as 5.72±0.67 d from the first flowering stage,and the average duration of flowering period of Lycoris aurea single plants was 7.27±0.59 d.The calculated results showed that the flowering synchronization index of Lycoris aurea single plants was 0.91±0.04,and Lycoris aurea had a high flowering synchronization at the single plant level.The OCI hybridization index was calculated to be 4,indicating that the breeding system is partially self-incompatible and the heterosis mechanism can be realized by pollinators.The natural fruiting rate of Lycoris aurea was high with 88.24%.According to the stigma pollination test,a small number of stigmas were pollinated during the bud stage of Lycoris aurea,and most of them were not pollinated.The stigmas have the strongest receptivity at the full flowering stage（early August）,although some stigmas still have receptivity until the wither stage.However,it is suggested to select the flowers at the full flowering stage for pollination in the study of cross breeding based on the mother of the Lycoris aurea.（2）The results of the pollen germination study of Lycoris aurea showed that 12 h of in vitro culture can be used as the observation time for screening the best in vitro pollen germination medium ratios of Lycoris aurea.The best pollen germination was achieved by using solid medium for in vitro culture at a culture temperature of 25℃.Calcium chloride had the greatest impact on pollen germination rate,followed by sucrose,and boric acid had the least impact.In terms of pollen tube length,boric acid had the greatest impact,followed by sucrose,and calcium chloride had the least impact.In promoting pollen germination in Lycoris aurea,the best medium ratio was15%sucrose+60 mg/L boric acid+100 mg/L calcium chloride,and the germination rate could reach 58.69%,and the best ratio to promote pollen tube elongation was15%sucrose+60 mg/L boric acid+50 mg/L calcium chloride,and the pollen tube elongation could reach 1883.88μm.The pollen germination rate of Lycoris aurea showed a regular variation at different developmental times,and there were significant differences.The pollen germination rate gradually increased during the development of Lycoris aurea from the bud stage to the bloom stage,and then showed a sharp decrease.In general,pollen viability and pollen volume were maintained at a high level in both the first and bloom stages,with the highest pollen viability of55.6%±6.24 in the bloom stage.（3）The effect of growth regulators on pollen germination in Lycoris aurea varied according to species and concentration.GA₃,2,4-D,IAA,IBA,and 6-BA at different mass concentrations showed significant inhibitory effects on Lycoris aurea pollen germination,while NAA at mass concentrations of 10 mg/L,15 mg/L,and 20 mg/L promoted Lycoris aurea pollen germination,when pollen germination rates reached43.78%±16.41,61.08%±6.85,and 51.34%±4.12,respectively.51.34%±4.12exceeded that of CK,while all other mass concentrations inhibited mutual pollen germination,indicating that moderate mass concentrations of NAA promoted Lycoris aurea pollen germination,while lower and higher concentrations inhibited Lycoris aurea pollen germination.（4）The results of the comparative study between the five staining methods and the germination method showed that the methylene blue staining method for determining the pollen viability of Lycoris aurea was similar to that of the in vitro germination method without significant differences,and could be used for the rapid determination of Lycoris aurea pollen viability.Although the results obtained by Alexander staining method were significantly different from those obtained by in vitro germination method,they were linear and the regression line was a good fit to the observed values,which can also be applied to the rapid determination of pollen vigor of Lycoris aurea.（5）The results of the study on the storage conditions of Lycoris aurea pollen showed that the germination rate of pollen stored at low temperature was significantly greater than that of pollen stored at room temperature,4°C could effectively maintain the viability of pollen in the short term,and-20°C to-80°C could effectively maintain the viability of pollen in the long term,with-80°C being the most effective storage.The pollen treated with 6 h drying had higher pollen germination rate than the other 0 h,9 h and 12 h drying treatments throughout the experimental storage period.In conclusion,the pollen collected at full bloom was the most suitable for research related to Lycoris aurea hybrid breeding,and the best germination was achieved by incubating the collected pollen on a solid medium of 15%sucrose+60mg/L boric acid+100 mg/L calcium chloride+15 mg/L NAA+0.5%agar at 25℃for 12 h.Using the in vitro germination method as a reference,it was determined that both methylene blue staining and Alexander staining could be used for the rapid determination of Lycoris aurea pollen viability in the field.The best results were obtained by drying Lycoris aurea pollen for 6 h and storing it at -80℃.